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The World’s Simplest Motor

In this activity, students create a simple motor using an electromagnet. 

In this activity, students see how an electric current running through a coiled wire creates a magnetic field. Two magnetic fields, repelling and attracting each other, can be used to convert the electrical energy of the battery into the mechanical energy of a spinning part.

This activity can take 20 minutes (including discussion) as a demonstration, or 45 minutes or more if students make one themselves.

Objectives

  • Describe the effect of applying electricity to a magnetic object.

Materials

  • Per Student:
    magnet wire (22 gauge)
    2 Paper clips
    Strong, flat magnet
    1 D cell battery
    Elastic (Rubber band)
    Sandpaper
    Battery holder or tape (to keep the battery in place)

Key Questions

  • What makes the coil spin?
  • What is happening when you can’t get the coil spinning quickly?
  • How did you solve the problem, and what does that tell you about how the motor works?

What To Do

  1. Make a tidy coil of magnet wire by wrapping it around the circumference of the battery. Slip the coil off of the battery and wrap the ends around the coil itself so it stays together. Keep the very ends of the wire free.
  2. Take the ends of the magnet wire and bend them so that they are perpendicular to the coil. Use sandpaper to scrape the coating off the ends of the wire.
  3. Bend the 2 paperclips into 2 cradles to support each end of the copper wire. The coil should sit in between the paperclips, and it should be free to rotate.
  4. Put the battery in the holder (or tape it down to steady it) and connect the 2 paperclips to the + and – end of the battery respectively. Use a rubber band to secure tightly. This should make a complete circuit.
  5. Place the magnet underneath the copper coil. If it doesn’t stick to the battery, use tape to hold it on.
  6. Now for the fiddling. The coil should spin quickly. If it’s not spinning, it may be unbalanced, too far from the magnet or not getting enough current through it.

Extensions

  • Use a compass to explore the magnetic field around the coil. Which way does the needle point near the coil? Which way does it point near the permanent magnet?
  • If you can get your compass inside the coil, which way does the needle point?